In the graphic arts photosensitive tacky-surfaced elements are used to define images and, particularly, multicolor images. A photosensitive element is first given an image-wise exposure resulting in the element exhibiting different degrees of tackiness in the exposed and unexposed areas. Following the image-wise exposure the latent image is developed by the application of particulate material, called toner, onto the surface. The tacky image area on the element causes toner to adhere thereto, thus developing the image. Thereafter excess toner particles are removed from the surface.
In contrast to the so-called xerographic toners which exhibit relatively free flowing characteristics, the particulate toner material used in conjunction with the developing system above discussed is characterized by its agglomerating tendencies. As a result, such toners are difficult to handle and tend to cake or resist flow. A variety of devices have been developed whereby such particulate toner may be applied to and removed from the tacky surfaces of the photo-element. Exemplary of a manually operable device for applying controlled quantities of the finely divided particulate toner is the device disclosed in U.S. Pat. No. 3,980,047 (Cohen et al.). U.S. Pat. No. 4,019,821 (Sandner) also discloses a manually operable toner applicator.
U.S. Pat. No. 4,069,791 (Tobias) is representative of an automated apparatus for applying particulate material to the image-wise tacky surface of a photo-element. The photo-element is carried along a transport path to a position beneath a toner hopper. The particulate material is dispensed from the hopper, the hopper having a sidewall which vibrates transversely to the direction of movement of the photo-element. The photo-element is then moved under a toner applicator which includes a brush pad oscillating transversely to the direction of movement of the photo-element to embed the particulate toner into the surface. A second agitating member oscillating transversely of the direction of movement of the photo-element removes excess toner from the photo-element.
The device shown in copending application Ser. No. 64,396, filed Aug. 6, 1979 in the name of Herbert Tobias, also discloses an apparatus for applying toner to the tacky surface of a photo-element. In this device the element advances through the apparatus between a pair of plates covered with pile fabrics. The fibers in the pile fabrics are slanted in the direction of advance of the photo-element. One of the plates is reciprocated in a direction parallel to the direction of advance of the element to thereby impart movement to the element. As the element passes beneath a hopper rotary motion is imparted to an applicator roll which dispenses particulate toner onto the surface of the photo-element.
Since the toner particles have a tendency to agglomerate and resist flow, it is advantageous to provide a toning apparatus wherein the hopper is vertically reciprocated toward and away from the transport path to fluidize the toner particles to faciliate flow thereof. Moreover, since it is believed that a "vertical patting" motion is most advantageous in embedding toner into the tacky surfaces on the photo-element, it is believed to be of advantage to utilize the vertical reciprocating motion imparted to the hopper to embed the toner into the tacky surfaces on the photo-element.